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<h2><a name="SECTION0019610000000000000000">
17.6.1 asynchat - Auxiliary Classes and Functions</a>
</h2>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><span class="typelabel">class</span>&nbsp;<tt id='l2h-3784' xml:id='l2h-3784' class="class">simple_producer</tt></b>(</nobr></td>
  <td><var>data</var><big>[</big><var>, buffer_size=512</var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
  A <tt class="class">simple_producer</tt> takes a chunk of data and an optional buffer size.
  Repeated calls to its <tt class="method">more()</tt> method yield successive chunks of the
  data no larger than <var>buffer_size</var>.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3785' xml:id='l2h-3785' class="method">more</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
  Produces the next chunk of information from the producer, or returns the empty string.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><span class="typelabel">class</span>&nbsp;<tt id='l2h-3786' xml:id='l2h-3786' class="class">fifo</tt></b>(</nobr></td>
  <td><var></var><big>[</big><var>list=None</var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
  Each channel maintains a <tt class="class">fifo</tt> holding data which has been pushed by the
  application but not yet popped for writing to the channel.
  A <tt class="class">fifo</tt> is a list used to hold data and/or producers until they are required.
  If the <var>list</var> argument is provided then it should contain producers or
  data items to be written to the channel.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3787' xml:id='l2h-3787' class="method">is_empty</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
  Returns <code>True</code> iff the fifo is empty.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3788' xml:id='l2h-3788' class="method">first</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
  Returns the least-recently <tt class="method">push()</tt>ed item from the fifo.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3789' xml:id='l2h-3789' class="method">push</tt></b>(</nobr></td>
  <td><var>data</var>)</td></tr></table></dt>
<dd>
  Adds the given data (which may be a string or a producer object) to the
  producer fifo.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3790' xml:id='l2h-3790' class="method">pop</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
  If the fifo is not empty, returns <code>True, first()</code>, deleting the popped
  item. Returns <code>False, None</code> for an empty fifo.
</dl>

<p>
The <tt class="module">asynchat</tt> module also defines one utility function, which may be
of use in network and textual analysis operations.

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><tt id='l2h-3791' xml:id='l2h-3791' class="function">find_prefix_at_end</tt></b>(</nobr></td>
  <td><var>haystack, needle</var>)</td></tr></table></dt>
<dd>
  Returns <code>True</code> if string <var>haystack</var> ends with any non-empty
  prefix of string <var>needle</var>.
</dl>

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